Olefin-based polymers, such as polyolefins and ethylene-vinyl acetate copolymers, are widely used for making various products, because they have good chemical stability, mechanical strength, electrical insulating ability, and dimensional stability and they are non-toxic and easily processable. However, olefin-based polymers have defects, such as susceptibility to discoloration (for example, yellowing) and reduced mechanical properties, due to oxidative degradation caused by heat, light, and oxygen.
It is well-known that an antioxidant may be used in a process for manufacturing a molding product from an olefin-based polymer to prevent the olefin-based polymer from oxidative degradation so as to enhance the mechanical property and thermal resistance of the olefin-based polymer. However, use of antioxidants might result in coloration and reduced processing stability of olefin-based polymers. In addition, an anti-acid agent may be used in a process for manufacturing a molding product from an olefin-based polymer to inhibit the degradation of the olefin-based polymer by an acidic substance. Nevertheless, anti-acid agents might result in coloration and reduced processing stability of olefin-based polymers.